1. Field of the Invention
The invention relates to a linear guide for moving parts and more particularly to a linear guide for moving parts on microscopes.
2. Discussion of Prior Art
A linear guide for moving parts on microscopes is described in German Utility Model 77 31 160. It has double guides on both sides, that is, the guided part is guided on two opposite sides respectively on two spaced-apart guide tracks. In order to adjust the play or the smooth running property of the guide, guiding takes place respectively only in one direction on two mutually opposite sides, while the guiding on the two other mutually opposite sides takes place in two substantially perpendicular directions. Such double guides on both sides have, in comparison with linear guides with only one guide track on each side, substantially smaller tilting moments and hence a greater rigidity.
A double guide on both sides is of course over determined by the two substantially V-shaped guide tracks on the one side and the two flat guide tracks on the other side; that is, wedge angles between the guided part and the guiding part cannot be compensated. Therefore only a very small guide play can be compensated, without leading to tight running. Thus for smooth running, high requirements are placed on the precision of the guide tracks, and also with respect to their parallelism, and with respect to their spacings.
The situation is similar for the guide according to British Patent 1,012,974, in which the guided part has three parallel round rods which are guided respectively between two rollers on the guided part.